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NEWBORN HYPOTONIA PANEL:
When a baby is born with severely hypotonic muscles three
different syndromes represent the most common genetic defects. In order to expedite diagnosis,
reduce the total cost of testing, and improve the ease of ordering, the tests for
Spinal Muscular Atrophy (SMA), Myotonic Dystrophy (DM) and Prader-Willi Syndrome (PWS),
have been combined into a single panel. Due to the nature of these of the
conditions, each one of them can appear in families with no apparent prior
history. For details of each condition, please refer to the individual tests.
REASONS FOR REFERRAL:
- Identification of the cause of a severely hypotonic baby.
- To assess the most probable long-term course of the condition.
- Prenatal diagnosis in the case of a fetus with little movement.
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TESTING METHODOLOGY:
- SMA: PCR amplification of the affected regions of the SMN gene and
digestion of the products to detect the loss of exons 7 and 8.
- DM: PCR amplification of the variable CTG repeat region
and
fluorescence size analysis; in conjunction with Southern Blot analysis of the myotonin
protein kinase gene
- PWS: Southern blot analysis using a SRNPN probe.
SPECIMEN REQUIREMENTS:
- Blood EDTA (purple top) tubes:
Newborn: minimum 1-2 mL
Child/Adult: prefer 2 tubes of 3-5 mL
- Prenatal testing: Please contact the
laboratory for instructions.
TURNAROUND TIME: 8 days (SMA); 3 weeks (PWS
& DM)
CPT CODES:
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